The Underworld is the all-Ghoul city/hideout located in downtown Washington D.C. More specifically, you can find Underworld housed in what was, before the massive nuclear attack, the Museum of History. It's easy enough to find if you're downtown, and chances are you've stumbled upon it during your travels as it is, so we'll assume you know how to get there. Once you arrive, head on inside and through to the concourse, and begin seeking out a Ghoul named Mr. Crowley. Chances are, he's in the Underworld's bar, The Ninth Circle.

When you locate him, begin speaking to him. As long as you're nice to him (or at least amicable), he'll tell you that you have a reasonably good sense of humor (for a human) and then begin talking to you about more pressing matters. It appears Mr. Crowley has a few issues with some humans on the Wasteland, and he wants retribution taken on these guys by way of the old "zombie-killing" technique -- a brutal shot to the head. He'll even hand over a Sniper Rifle for you to use before giving you the four names of the men he wants slain. As for why these men should be killed, you'll need to talk to Ghouls on your own to figure that out. The locations of the men you have to kill and how you should go about killing them (or not) is all below.

We'll go in order of the steps given to us in-game. First, we'll go after Dave, who is located at a place succinctly called The Republic of Dave. The Republic of Dave is located in the far northeast corner of the Capital Wasteland, which will force you to walk a long way from nearby locations you might have already uncovered. We sprang our assault from the Clifftop Shacks due west of the Republic of Dave, but you might have a better place to go from. Vault 92 and Old Olney, both due west of the Republic as well (but closer than the Shacks) are another good starting point. For those that have done minimal searching, Minefield might be your best bet. From there, you can travel in a northeasterly direction until you arrive.

Finally, you'll glimpse the unimpressive Republic of Dave from afar. It's really just a group of some rusty metal shacks surrounded by a half-destroyed chain link fence. However, there's only one way to get in (we're assuming you've never been here before). When you arrive at the front gates, a little girl named Flower will intercept you. Convince her you aren't a threat and she'll not only let you in, but lead you directly to President Dave (her father). How convenient.

Follow Flower as she leads you to Dave's home, which is the shack located furthest from the front gate. Once you're inside, you don't have to explore if you don't want to, though you may want to speak to some of the various people you find inside to learn more about the place, especially if you are going to kill Dave, which will make them turn on you (thus forcing you to kill them). When you're ready, you can then speak to Dave, who is callously leaning up against the wall of his office as if he were the cat's meow. Assuming this is the first time you speak to him, he'll ask you all sorts of questions and you can deal with it how you want. Remember why you're here, though.

This doesn't have to end violently. In fact, you can get Dave's key (which your contractor will require as proof that he's dead) by convincing him to give it to you or by stealing it from his pocket. But we decided to turn our Sniper Rifle on the cocky president of five people. Remember, you have to aim for the head and kill him by striking the head to get the full bounty. But after you're done eliminating Dave from the scene, you're going to have to deal with a group of his cronies as well, both in the house and once you're outside. Kill them (or simply run away). It's time to move on to our next target, regardless of how you decided to deal with this. Be sure you don't leave without the proof of his death (supposed or real) in the form of Dave's Special Key.

Next on Mr. Crowley's list is Dukov. Dukov's Place (which is quite literally the name of the establishment where you'll find Dave) is much, much easier to find and more convenient to travel to than the Republic of Dave. While Dave's Republic was located far, far in one of the corners of the Capital Wasteland, Dukov's Place is located downtown in Washington D.C. In fact, if you teleport anywhere even remotely close to it (such as the Tepid Sewers, Anchorage War Memorial or Dupont Station), getting there shouldn't take any more time than a minute or two, especially if you run into no enemies en route.

When you enter Dukov's Place, you'll find quite the scene. Dukov is a playboy of sorts, and he's surrounded himself with two scantily-clad women who do his bidding. Approach Dave and he'll automatically engage you in conversation (if this is your first visit to his house, which we're assuming it is). Pick his brain about his incredible situation (all the more incredible when you consider the nuclear holocaust outside), and he'll tell you that in return for the services of his two women friends, they are kept safe from the horrors and dangers of the Wasteland. Nice deal, Dukov!